Fig. 3

NRP1 is associated with the claudin-low signature in breast cancer cell lines and promotes proliferation. a Heatmap showing NRP1 mRNA expression across luminal, basal A, basal B and claudin-low human breast cancer cell lines, as well as association with core claudin-low signature genes [10, 28]. NRP1 mRNA expression in b luminal, basal A and basal B breast cancer cell lines, C claudin-low versus non-claudin-low cell lines, and association with key claudin-low markers di claudin 3 (CLDN3) and dii vimentin across breast cancer cell lines. E Flow cytometry analysis of NRP1 expression across breast cancer cell lines representing different intrinsic subtypes and the claudin-low (CLDN^low) subtype. f Western blot analysis of NRP1 expression in BrCa cell lines including luminal A (LumA; T47D and MCF-7), luminal B (LumB; MDA-MB-361), HER2⁺ (BT-474, HCC1569 and SKBR3), basal (BT-20 and MDA-MB-468) and claudin-low (SUM159, MDA-MB-231 and HS578T) cells, with GAPDH loading control. g Western blot showing NRP1 expression in claudin-low cell lines (MDA-MB-231, BT549, SUM159 and HS578T) at day 3 post-transfection with NRP1 siRNA (siNRP1 [1] or siNRP1 [2]) or non-targeting control siRNA (siNT). h Cell viability of claudin-low cell lines (MDA-MB-231, BT549, SUM159 and HS578T) at 0, 1, 2, 4 and 7 days after transfection with NRP1 siRNA (siNRP1 [1] or siNRP1 [2]) relative to siNT as measured by CyQuant™ DNA quantification assay; n = 3. Error bars represent SEM, *p ≤ 0.05; **p ≤ 0.01; ***p ≤ 0.001, ****p ≤ 0.0001